There are a lot of application scenarios of multipoint to multipoint multicast in the current network, and the application scenarios of multipoint to multipoint multicast are to bear a broadcast packet in a layer 2 virtual local area network (Virtual Local Area Network, VLAN for short) onto a corresponding layer 3 multicast group via overlay (Overlay) technology, and emulate multipoint to multipoint local area network applications in the layer 2 VLAN such as unknown unicast flooding, broadcast and etc. through a layer 3 multicast group distribution tree. In a multipoint to multipoint multicast scenario, each edge router is connected both to a multicast source and to a receiver, under this scenario, it is more suitable to adopt a bidirectional multicast distribution tree, where a multicast data packet can be sent from a leaf to a root, and also can be sent from a root to a leaf. Currently, a bidirectional multicast distribution tree in a network is usually constructed by a bidirectional protocol independent multicast (Protocol Independent Multicast, PIM for short).
During implementation of embodiments of the present invention, an inventor founds that at least following problems are existed in the prior art: in the multipoint to multipoint multicast scenario, the bidirectional PIM protocol is adopted when multicast needs to be implemented, and at the mean time, an interior gateway protocol (Interior Gateway Protocol, IGP for short) needs to be run as a unicast routing protocol, so two sets of protocols need to be operated and maintained simultaneously, and the operation and maintenance are complex.